Portable warm air humidifier

ABSTRACT

A portable warm air humidifier for delivery to a room a steam air mixture of uniform moisture and at a temperature that does not cause sensation of pain. A steam ejector is used to mix the steam from an evaporation chamber with the air entering the humidifier with the advantage, among others, of eliminating the need for motors and blowers. A difference in the water level between a water supply compartment and the evaporation chamber provides a constant pressure in the evaporation chamber which is necessary to drive generated steam through a steam nozzle communicating with the steam ejector. The dimensions of the steam nozzle are determined in relation with the rate of steam generation in accordance with steam velocity to effectively eliminate or minimize the noise normally associated with the passage of steam through a nozzle. The invention is also well utilizable in a humidifier having a filter medium to filter particulates from the air notwithstanding the drop in pressure of the air across the filter medium from the outside to the interior of the humidifier.

BACKGROUND OF THE INVENTION

[0001] invention relates to a portable, electric air humidifier, moreparticularly to an improved warm-air humidifier.

[0002] This application is a continuation-in-part of applicant's pendingU.S. patent application, Ser. No. 07/606,938 filed. Oct. 31, 1990, whichin turn is a continuation of applicant's U.S. Pat. No. 5,014,338 issuedMay 7, 1991.

[0003] Air humidifiers have been found to be important in controllingthe environment in homes during very dry weather, or in winter wheneveroutside air of low temperature is drawn inside and heated, causing therelative humidity in the home to be lowered to an uncomfortable degree.

[0004] Portable humidifiers are well known in the art, and may beclassified as follows:

[0005] 1. Steam generators which comprise a water container and anelectric heating element submerged in the water, there being providedsafety devices for switching off the current as soon as the water leveldrops below the heating element. A flow of hot steam is blown directlyinto the room to be humidified and there is always the danger of aperson, especially a child, being scalded whenever he comes into contactwith the jet of steam ejected, typically, at a temperature of about 212°F. Furthermore, the container of hot water, when overturned, may causeserious injuries to the person nearby.

[0006] 2. Porous medium humidifiers generally include a porous mediumstructure partly submerged in cold water contained In an open vessel anda blower unit drawing air through the porous medium structure. Theporous medium is either in the shape of a disc or a drum with part ofthe medium dipping into the water, which is slowly rotated while air isblown through the portion above the water level, thus carrying humidityinto the room; or it is in the form a stationary body adapted to drawwater into the upper non-immersed part by capillary action, from whereit Is carried into the room by air blown therethrough.

[0007] 3. Ultra-sonic humidifier generally comprise a container filledwith water which is brought to a vibration by high-frequency vibratormeans which causes the water to be atomized. An air steam directed ontothe water surface carries the mist into the room to be humidified.

[0008] The major drawback of both the two latter appliances is the factthat the water staying in the container is not heated to boiling pointas in the steam generator and, therefore, is susceptible to the growthof microorganisms which are subsequently carried by the air stream intothe room and ingested by the people staying there.

[0009] 4. Warm-air humidifiers share the benefits of steam generators inthat growth of micro-organisms is forestalled by heating the water toboiling point. Also, warm-air humidifiers avoid the drawback of hotsteam entering the room, since in this type of humidifier the steam iscarried into the room as a mist mixed with air, at a temperature to beselected by judiciously choosing the ratio of steam and air.

[0010] A typical warm-air humidifier is described in U.S. Pat. No.4,564,746: it includes a heated evaporation chamber which is enclosed toprevent leakage or damage and a fan adapted for dispersing the generatedsteam into the room via a cabinet passageway. The evaporation chamber ismounted on tracks which permit its sliding out of its enclosure and isthus easily accessible for cleaning and servicing. The heating elementwhich is operationally enclosed in the chamber is attached to a coverwhich is likewise movable out of the humidifier cabinet for cleaning andservicing.

[0011] The drawback of this humidifier is its relatively intricate andexpensive design: according to the description, the heating element isattached to a movable cover which is provided with flexible tubing andmust be moved upwards on vertical tracks in order to clear the top ofthe water enclosure, permitting the latter to be slide out sideways. Itrequires a significant amount of space and cannot be serviced except bya skilled person.

[0012] The humidifier disclosed in applicant's U.S. Pat. No. 5,014,338and pending patent application Ser. No. 07/606,938 and in the presentapplication have similar or substantially the same structure except aswill be brought out hereinafter. For one thing, a steam ejector isprovided in the present application which takes the place of the motordriven blower disclosed in applicant's mentioned patent and pendingapplication. In terms of similar concepts and structure which are commonto the mentioned patent, pending application and present application,the various Embodiments each employs base means having a water supplycompartment separated into a filling compartment and a main compartmentwhich is in communication with an evaporation chamber to provide waterthereto for boiling. The evaporation chamber has an enclosure whichprojects into the main compartment and a heater is carried within theenclosure, the lower edges or the wall of the enclosure is spaced fromthe floor of the main compartment to form a passageway, whereby waterflows therethrough to immerse the heater within the water. Structure,either in the form of removable trays or a displaceable housingcontaining the evaporation chamber, is utilized to obtain access to thetrays or the heater for cleaning purposes.

[0013] Humidifiers employing motor driven blowers, such as is found inapplicant's U.S. Pat. No. 5,014,338 and in pending application Ser. No.07/606,938 have many benefits arid advantages. On the other hand the useof warm air humidifiers utilizing motor driven blowers an at timesdeemed objectionable when used in nurseries and in bedrooms as beingnon-conducive to sleep because of the mechanical and aerodynamic noiseassociated with motor driven blowers. In addition, the presence of highhumidity to which motor shafts are exposed creates rusting problems withthe resulting binding of the shafts to the bearings. Obviously, thiscreates expensive maintenance problems and may inhibit the user fromobtaining service because of the expense.

[0014] Certain criteria are desired in warm air humidifiers to maximizethe desirability and efficiency of such devices for the user. Onecriterion is to maintain the steam-air mixture at a predeterminedtemperature which ranges between 37° C. and 65° C. (99° F.-149° F.)where the lower end of the range approximates human body temperature andthe upper end represents a value at which the steam air mixture stillmay be brought into contact with a person's hand without the sensationof pain. Another criterion is to provide a uniform mixing of air andsteam resulting in an even temperature profile at the outlet grille andavoiding non-uniform degrees of air saturation as well as localrecondensation on portions of the grill.

[0015] The following relevant prior art has been found in apatentability search: U.S. Pat. No. 4,635,630; Soviet documents no's.SU1174569A and 883,637.

[0016] Accordingly it is an object of the present invention to providean improved and novel non-motor driven warm-air humidifier whichutilizes a simple and inexpensive structure and still obtains resultsequivalent to or better than those obtained by humidifiers employingmotor driven blowers.

[0017] It is another object to provide an improved and novel humidifierwhich provides for the proper and uniform mixture of steam laden airhaving the proper ratio of air and steam and substantially uniformtemperature profile at the outlet grille.

[0018] It is a further object to provide an improved and novelhumidifier which employs a steam ejector in place of a motor drivenblower and which exhibits significantly less objectionable noises thanthose employing motor driven blowers.

[0019] It is a still further object to provide a novel and improvedhumidifier which utilizes a steam ejector tube having a restrictedthroat portion therein and which is dimensioned and positioned inrelation to a steam nozzle in which steam flows at a certain velocityand produces a steam air mixture of the proper saturation andtemperature substantially noise free or of minimum noise.

[0020] Another object is to provide a novel and improved gravitywater-feed humidifier in which the constant pressure to drive thegenerated steam through a steam nozzle is maintained by a differentialhead of water existing between the steam generation compartment and thewater supply compartment.

[0021] Further objects ad advantages of the present invention willbecome obvious to one skilled in the art in the following description ofthe invention and the claims.

SUMMARY OF THE INVENTION

[0022] The warm air humidifier, of the present invention, includes anevaporation chamber in the shape of an inverted cup which is providedwith a steam nozzle in its top portion and the chamber contains anelectric resistance heater close to its open bottom end. In a preferredembodiment, the evaporation chamber is capable of containing only asmall volume of water, thus promoting rapid start operation. The openbottom end is immersed in the main compartment of a water supplycompartment which also includes a filling compartment supplied withwater from a portable jug positioned on a base which includes the watersupply compartment. The water supply compartment is kept filled withwater to a predetermined level by the jug allowing water to flow intothe compartment only as high as the rim of the neck of the jug. Thepressure within the evaporation chamber, which is generated by the steamtherein, is maintained constant by a differential head which exitsbetween the higher level of the water in the water supply compartmentand the lower level of the water in the evaporation chamber.

[0023] Vertically disposed above the steam nozzle is a steam ejectortube having its lower end in spaced proximity to the steam nozzle,whereby steam from the steam nozzle flows through the steam ejectortube. The tube has a narrow and restricted portion which, in operation,creates a region of low pressure to thereby induce a flow of air withinthe housing to mix with the steam to produce an air-steam mixture. Thepresent invention takes advantage of certain phenomena as follows:

[0024] 1. The high velocity jet stream from the nozzle, while flowingthrough the “still air” in the ejector tube will cause air next to it tomove with it through the exertion of a shear-force. That moving air thenwill carry along with it the adjacent layers of air particles, which inturn carry adjacent layers until the boundaries of the tube are reached.By properly designing and dimensioning and positioning the relevantcomponents involved, entrainment of air with steam to provide a desiredratio of air to steam and temperature may be obtained.

[0025]2. The negative or low pressure created within the steam ejectortube, which is dependent upon the dimensions of the “draft; of the tube,will influence the flow of the air to be treated into the humidifier,especially were provision must be made to overcome the pressure dropoccasioned by reason of the air having to flow through a filter mediumwhen the humidifier is to remove particulates from the air to betreated.

[0026]3. A “buoyancy” phenomenon is utilized in the present invention.As the steam mixes with the air the mixture becomes warm and humid, thusattaining a specific gravity lower than the surrounding dry cooler air,consequently, the air steam mixture adds another driving component tothe flow of the mixture and rises through the tube to enhance thedrawing in of fresh or cool air from the bottom of the tube, much as inthe well known “atmospheric hyperbolic” cooling towers.

[0027] The preset invention incorporates and utilizes these phenomena toprovide a simplified and effective low cost warm air humidifier whichminimizes and avoids many of the problems associated with other portablehumidifiers, particularly those employing motor driven blowers formixing air and steam for delivery to a room in which such humidifiersare placed.

BRIEF DESCRIPTION OF DRAWINGS

[0028]FIG. 1 is a vertical section through the warm-air humidifier ofthe invention and through an inverted water container in position on thebase means of the humidifier;

[0029]FIG. 2 is a vertical section through the bottom portion of thehumidifier illustrated in FIG. 1, showing the tray in lowered positionready for removal;

[0030]FIG. 3 is a section through the warm-air humidifier along line A-Aof FIG. 1;

[0031]FIG. 4 is an enlarged fragmentary vertical section through the topportion of the humidifier illustrated in FIG. 1;

[0032]FIG. 5 is a vertical section of a second embodiment of thewarm-air humidifier containing a hinged evaporation chamber, shown inposition on the base means;

[0033]FIG. 6 is a vertical section of the warm-air humidifier FIG. 5showing the evaporation chamber displaced away from the base means;

[0034]FIG. 7 is a section in elevation, of a third embodiment of thepresent invention;

[0035]FIG. 8 is a section, in elevation, taken along the line 7-7 ofFIG. 7;

[0036]FIG. 9 is an enlarged view of the steam ejector tube and of thesteam nozzle to graphically show the flowing streams of steam and air;and

[0037]FIG. 10 is a graphical representation of a velocity distributionplot of the phenomena occurring within the steam ejector tube of FIG. 9:

[0038]FIG. 11 is an isometric view of the tray shown in FIGS. 7 and 8.

DETAILED DESCRIPTION OF THE INVENTION

[0039] The components of the warm-air humidifier, as shown in FIGS. 1and 2, are enclosed in a housing I including a base portion 1 and a topportion 2, the base being configured to support a water jug II inupside-down position. The base contains a drawer III of trapezoidalcross section which forms together with a sloping inner wall 10 of thebase, a “V”-shaped trough 11. A tray IV is supported by the respectivesloping walls 10 (of the housing) and 50 (of the drawer), whereby thecontours of two opposite side walls 40 and 41 of the tray correspond inslope to the inclination of the two walls, while the tray bottom 42 issubstantially flat. The tray includes a main compartment 43 and afilling compartment 44, in proximity to the drawer wall 50, which areseparated by a partition 45 perforated by a connecting port 46. Avertical pin 47 projects from the bottom of the filling compartment andconnects with a spring-supported valve 20 in the neck opening 22 of theinverted jug II. In order to keep the drawer in position inside thehousing a tongue 38 projects upwardly from the bottom of the housing andengages an opening 39 in the bottom of the drawer when this is in closedposition.

[0040] The top portion of housing 2 includes an evaporation chamber 30in the shape of an inverted cup which extends into the base portion 1and into the main compartment 43 of the tray, stopping short of the flatbottom 42 with a narrow gap remaining between the lower rim of thechamber and the bottom. The chamber top is stepped, forming a higherportion 31 a which contains a steam nozzle 32, and a lower portion 31 binto which a flask-shaped member 33 is inserted and hermetically closedto prevent steam from escaping therethrough. Member 33 holds athermostatic switch 35, as well as a set of levers 36 serving forresetting the switch by means of knob 37. The tray, as well as thebottom of the evaporation chamber is filled with water, its upper levelbeing defined by, the lower rim 21 of the valve 22 in the neck of thejug II. An electric heater 34 is fully immersed in the water, and isheld at its raised portion 34 a in intimate contact with the member 33by means of a clip 52. The heater is switched off as soon as the waterlevel drops below the raised portion 43 a of the heating element due tolack of water in the jug.

[0041] For operation of the humidifier, the jug II, full of water, isplaced with its valve 22 onto the filling compartment whereupon the pin47 urges the valve body 20 upwards off its seat and permits water toflow into the tray. Water flows out of the filling compartment 44 intothe main compartment 43 through the port 46 in the partition 45, thelevel being defined by the rim 21 of the jug's neck; for the reason thatno air can flow into the jug through the neck as soon as it is coveredby water and, obviously no water can flow out.

[0042] Due to evaporation, the water level in the tray will drop belowthe height of the rim of the jug, permitting more water to enter thetray and keeping it filled to the predetermined level. For the purposeof cleaning the tray, the drawer III is pulled out of the housing,causing the tray to slide down along the inclined wall 10 of the housingas shown in FIG. 2 of the drawing. At the same time, the pin 47 in thefilling compartment is taken out of contact with the valve 20 of thejug, thereby closing the neck opening and preventing water from flowingout into the tray. The drawer III can now be withdrawn from the housingand the tray IV can be taken out.

[0043] A vertically disposed steam ejector tube 84 is provided withinhousing I immediately above the steam nozzle 32. Tube 84 is made of anysuitable material and preferably may be formed from a plastic, such as,polypropylene, which is molded to the preferred shape disclosed. At itslower portion tube 84 is flared outwardly and then narrows to a throat86 and thereupon the tube flares outwardly and towards the top 88 of topportion 2 of housing I. Top 88 has an outlet opening 90 (FIG. 1), thewalls of which seat the circumferential edge of tube 84 at that point. Agrille 92 is provided at opening 90 to direct the flow of air from tube84 and into a room. Housing I may also include side wall 94 having aremovable air filter 7.

[0044] Since the compartment 43 and 44 are in liquid communication witheach other the water level in both compartments will be the same height.When heating element 34 is energized, the water in compartment 43 andparticularly in evaporation chamber 30 begins to boil and steam isformed. The pressure of the generated steam, as present in the space inevaporation chamber 30, forces the level of water therein to a levelbelow the level of the water in compartment 43 outside of evaporationchamber 30 and in compartment 44, to provide a differential head whichin effect maintains the pressure within evaporation chamber 30. Thispressure forces or drives the steam out of evaporation chamber 30through steam nozzle 32 at a predetermined velocity. The existing steamthen flows up into steam ejector tube 84 where it enters throat 86. Therestricted dimensions of throat 86 create a region of low pressure,which in conjunction with other phenomena to be described hereinafter,sucks or draws air in from the interior of housing I to form a steam-airmixture which discharges through outlet opening 90 in the top 88 of thetop portion 2 of housing I.

[0045] The use of the steam ejector concept in the present inventionrequires an understanding of certain phenomena which makes practical theapplication of this concept to gravity feed portable warm airhumidifiers. A steam ejector requires a high velocity of steam from anozzle ad through an ejector tube in order to provide a proper mixtureof steam and air having the desired ratio, as well as temperature.Firstly, a consideration of the steam velocity should be made, it beingknown that the velocity of steam through the nozzle is a function of thefollowing:

[0046] A=The cross-section area of the nozzle expressed in centimeterssquared (cm²)

[0047] G=Rate of steam generation in grams per second (Gr/sec)

[0048] ρ=The density of the steam in grams per centimeter cubed (g/cm³)

[0049] Thus;

V(cm/sec)=G÷(ρ×A)

[0050] The rate of steam generation is a direct function of the powerinput

G=k×EP

[0051] Where

[0052] EP=electric power in watts

[0053] K=a constant dependent on the latent heat of water

[0054] and

[0055] According to Bernouli's equation, the pressure required to drivethis steam through the nozzle at a velocity (V) is

P÷ρ=V2+2 g (g=gravitational acceleration)

[0056] Applying the foregoing to the present invention, the pressure(AP) within evaporation chamber 30, translates to a difference in waterlevel (ΔH) by which the water level in evaporation chamber 30 is lowerthan the water level in compartments 43 and 44 which supply water toevaporation chamber 30. As will be obvious from the description above,as the water is boiled off in evaporation chamber 30, the water thereinslowly recedes. This causes water to seep into evaporation chamber 30from compartments 43 and 44 and through the space between the loweredges of evaporation chamber 30 and bottom 42 in compartment 43 toreplenish the water boiled off. In the structure of the humidifieremployed, it is found that the head available is in the range of ½″ to¾″ or 1.25 cm to 2.0 cm which furthermore provide steam velocities of1,000 to 3,000 feet per minute (fpm) or 5-15 meters per second (m/sec).Since an objective of the present invention is to reduce the noise ofoperation of a humidifier, steam velocities through steam nozzle 32 areof a humidifier, steam velocities through steam nozzle 32 are maintainedbelow 2,000 fpm, or a rate of steam flow below 0.5 gr/sec cm² because togo above it would result in objectionable “hissing” sounds.

[0057] The action of the steam flow through ejector tube 84 to producethe desired results with the present invention may be explained byreference to FIGS. 9 and 10. In FIG. 9 the steam jet emerging from steamnozzle 32 is at a high velocity and after leaving the nozzle enters anarea known as “vena contracta” whereupon it starts diverging. The steamjet while traveling through the “still” air causes the air next to it tomove with it through the exertion of sheer-force.

[0058] The movement of air next to the steam jet will carry along theair particles next to it, and so on, until a velocity profile as shownin FIG. 10 is achieved. As the steam jet moves further away from thenozzle it expands and entrains the air until a substantially uniformmixture of air and steam is established in an around the narrowest areaof the tube, which is the throat 86. As the mixture passes the throatand moves towards the upper end of the tube, the mixture rises due tothe upwards impetus provided by the steam and by the buoyancy of thewarm, moist air mixture which is lighter than dry cool air.

[0059]FIG. 10 illustrates, in a graphic manner, the air and steamvelocity distribution as measured along the “ref. line” of FIG. 9. Theline described as “velocity profile” is the locus of all the individualvelocity measurements taken along the “ref. line” of FIG. 9. It shouldbe noted that along the “ref. line” there is still very little mixing ofair and steam and therefore a region of pure steam and pure air can beidentified, as pointed out by the terms “steams” and “air”.

[0060] It was found in constructing the humidifier of the subjectinvention that certain dimensions of the ejector tube 84 had to beadjusted as follows:

[0061] As was brought out above, the rate of steam flow out of steamnozzle 32 is preferably maintained below about 0.5 gr/sec cm².Furthermore, in order to obtain an outlet moist air temperature betweenabout 42° C. and about 65° C., the ratio between the throat diameter andthe distance of throat 86 from the steam nozzle 32 should be in therange of about 0.5 to about 0.75.

[0062] Moreover, it was also determined that the ratio of the diameterof the steam nozzle 32 to that of the throat of the ejector tube 84should be in the range of about 0.1 to about 0.25.

[0063]FIGS. 5 and 6 show another embodiment of the present invention. Inthis warm-air humidifier, top portion 2 is hinged, allowing easy accessto the tray IV. In FIG. 5, illustrating the resting of the top portion 2on the base portion 1, the lower portion 31 b of evaporation chamber 30is surrounded by the tray IV area. A hinge assembly, comprising a hinge71 and a hinge support member 70, are attached to the jug supportplatform 72, allowing the top portion 2 of the housing I to be moved toan open position as shown in FIG. 6. These figures also show anembodiment of the invention which does not include a drawer. In thisembodiment, base 60 supports the tray bottom 42. When the top portion 2is moved to its open position, the tray IV is exposed, allowing its easyremoval.

[0064] A third embodiment of the present invention is disclosed in FIGS.7 and 8 incorporates much of the components and concepts found in FIGS.1 through 6 and FIGS. 9 and 10 except for some slight differences instructure as will become apparent from the description that follows.

[0065] Referring now to FIGS. 7 and 9, the portable warm-air humidifieris generally designated by the reference character 112 and includes awater container 114 disposed in juxtaposition with a housing 116, bothof which are seated on a base 1118 provided with feet 120 for placementon a flat surface (not shown). Water container 114 is provided at itstop (FIG. 7) with a convenient handle 122 situated in a recess 124 topermit the manual grasping of the handle 122 to remove and carry thecontainer from base 118. The bottom of container 114, as better seen inFIG. 7, has a neck 126 with external threads 128 on which a cap 130 maybe tightened. A spring biased valve 132 (springs not shown) having avalve steam 133 disposed in cap 30 and is normally biased for seating onthe walls 134 of an opening 136. Extended wing members 138 are providedto assist in the screwing and unscrewing of cap 130 from neck 126. Afterthe container is filled and capped it is positioned as shown in FIG. 7where it is supported on base 118 on integrally formed hollow projectssupports 139 (one shown in FIG. 7).

[0066] Base 118 is substantially hollow and accommodates a removabletray 140 (shown in FIGS. 7, 8 and 11) resting on a floor 144 of base 118and the tray has a filling compartment 142 to receive neck 126 ofcontainer 114. Tray 140 corresponds to tray IV in the first and secondembodiments herein as seen in FIGS. 1-6, in terms of each being easilyassessed and removable for cleaning. Furthermore, the trays of eachembodiment has a filling compartment and a main compartment. A floor 145of compartment 142 has an upstanding molded pin 146. As seen in FIG. 7,when container 114 is positioned on base 118, pin 146 engages valvesteam 133 to displace valve 132 upwardly, permitting water to flow fromthe container through opening 136 into a filling compartment 142 of tray140. Tray 140 has a second or main compartment 150 formed integrallywith compartment 142, to the left of the latter as seen in FIG. 7. Anupstanding post 152 is formed integral with floor 144 of base 118 and ispositioned between compartments 142 and 150 between upstanding walls 154of tray 140. Compartment 142 is substantially circular in horizontalcross section to accommodate neck 126 whereas compartment 150 issubstantially rectangular in horizontal cross-section. Compartments 142and 150 of tray 140 are in communication with each other in that waterfrom compartment 142 readily flows therefrom into compartment 150,whereby the level of water in compartment 150 will always be a the levelin compartment 142.

[0067] Housing 116 is provided with a rectangular shaped floor 160 whichsubstantially seals off the interior of housing 116 from compartment 150of tray 140 except for an opening in which the lower portion of a steamnozzle 162 is seated. As better seen in FIG. 8, nozzle 162 has anenlarged circular lower portion 164 leading to a narrowed andsubstantially cylindrical jet opening 166. Floor 160 has integrallyformed therewith a depending wall 168 which extends perimeterically ofthe floor and projects downwardly into compartment 150 of tray 140 toform an evaporation chamber 169. The wall 168 is positioned in closeproximity to the walls 170 of compartment 150. The lower edges of wall168 also extend close to the floor 145 in compartment 150 but are spacedtherefrom as to permit water in tray 140, and particularly compartment150, to readily flow between compartment 150 and evaporation chamber169. An electrical heating element 172 is provided in evaporationchamber 169, which when energized, heats the water to boiling togenerate steam therein which escapes chamber 169 through steam nozzle162. A plate or baffle 174 is secured adjacent to lower portion 164 ofnozzle 162 and in the path of flow of steam to interrupt and minimizethe discharge of water droplets from the compartment with the steam, aswell as to muffle to some extent, the boiling sound of water.

[0068] The outer sidewalls 204 of housing 116 has an extension or lip206 which projects below floor 160 and into compartment 150 of tray 140for engagement by a latch 208 which is mounted on post 152 for pivotalmovement by a screw 210. When container 114 is removed from base 118,access may be obtained to latch 208, to pivot it out of engagement withlip 206 to permit the housing 116 to be lifted off of base 118 andthereby allow access to heater element 170 for purposes of cleaning andthe like.

[0069] The present invention as embodied in the third embodiment shownin FIGS. 7 and 8 operates in similar manner as the first two describedembodiments in the generation of steam in admixture with air thehumidifier of the third embodiment, as is obvious from the descriptionand explanation hereinbefore, differs in that the housing containing theevaporation chamber may be removed completely from the base whereas inthe second embodiment the equivalent structure is pivoted to the base asat 71 (see FIGS. 5 and 6). It is apparent that there is no basic changein concept in that either structure permits displacement of theevaporating chamber from the base to obtain easy access to the heaterelement. Also, the latching structure which includes latch 208 and lip206, permits the positive latching of housing 116 on the base 118.

[0070] Steam ejector tube 84 preferably is in the configurationdisclosed in the drawings although the present invention contemplatesthe usage of a steam ejector tube which is straight or angled (ratherthan curved) or which does not have a restricted throat portion.However, these variations would result in a loss of efficiency of tube84 as would be understood from reading points 1, 2, and 3 in the“summary of the invention” in this patent.

[0071] In terms of modifications of the structure disclosedhereinbefore, the present invention also contemplates an evaporationchamber in which the lower wall engages the bottom of the tray ratherthan spaced therefrom. In such event, openings would be providedcircumferentially of the lower wall to permit water to enter theevaporation chamber from the main compartment. Although the operation ofthe humidifier of the present invention would not materially change, aproblem would arise in that the openings, in time, would become cloggedby deposits from the water or other liquids used, to thereby impede theflow of water between the main compartment and the evaporation chamber.

[0072] From the foregoing, it is apparent that the present inventionprovides an improved and novel humidifier which utilizes a simple andeffective steam ejector tube in combination with a steam nozzle throughwhich a high velocity jet is produced under the constant pressure byreason of a differential head of water in the water supply compartmentas constituted by the main compartment and the filling compartment ofthe base.

[0073] By utilizing the phenomena of entrainment, negative pressure andbuoyancy a uniform and desired mixture of steam and air at a temperaturebelow the painful range is obtained without the use of relativelyexpensive motor driven blowers and the like, as well a components withmoving parts. The invention thus obviates the need of fans, motors,electric controls and the like, and the assembly costs required of themas well as maintenance costs. Furthermore, the pressure drop through theair filter, where used, is overcome by the present invention which addsto the value of same.

[0074] Although several embodiments of the present invention have beendisclosed and described herein, it may be readily understood that othervariations of the invention may be practiced which still will beembraced by the spirit of the invention and covered by the claims whichfollow.

What is claimed is:
 1. A warm-air humidifier comprising, a base, ahousing on said base, and having an air inlet and an outlet, anevaporation chamber in said housing, means for delivering water from awater container to said evaporation chamber, a heater for heating waterin the evaporation chamber into steam, and an ejector chamber, in fluidcommunication with the outlet in the housing, and suitable for mixingsteam from said evaporation chamber with air.
 2. A portable warm airhumidifier comprising, a water supply compartment, an evaporationchamber having an upper closed end and a lower end in communication withthe water supply compartment for receiving water therefrom, means forheating the water in the evaporation chamber to create a body of steamwithin the upper portion of said chamber above the body of water in thelower portion of said chamber, a steam nozzle disposed in the closedupper end of the evaporation chamber permitting the escape of steam fromsaid evaporation chamber, the level of the water in the water supplycompartment being maintained higher than the level of the water in theevaporation chamber during the operation of the humidifier to maintain aconstant pressure within the evaporation chamber on the body of steamtherein to assist in the flow of steam through said steam nozzle, ahousing having an inlet for receiving air from outside the humidifierand an outlet for discharging a mixture of steam and air from saidhousing, and a steam ejector tube within said housing and injuxtaposition with but spaced from the steam nozzle to receive the flowof steam issuing through said steam nozzle, said steam ejector tubehaving a restricted throat portion which upon passage of airtherethrough causes a region of low pressure therein to draw air fromoutside the tube in admixture with the steam to thereby emit therefrom asteam-air mixture which exits the housing through said housing outlet.3. The warm air humidifier of claim 2, wherein a filter medium isprovided in the inlet to said housing to remove particulates in the airentering said housing.
 4. The warm air humidifier of claim 2, whereinthe difference in heads of water in the water supply compartment and inthe evaporation chamber is in the range of ½ inch to ¾ inch.
 5. The warmair humidifier of claim 2, wherein the rate of steam flow out of saidsteam nozzle is maintained below 0.5 grams/sec cm².
 6. The warm airhumidifier of claim 2, whereas in the ratio between the throat diameterof said steam ejector tube and the diameter of the steam nozzle is inthe rage of 0.1 to 0.25.
 7. The warm air humidifier of claim 2, whereinthe ratio between the throat diameter of said steam ejector tube and thedistance of the-tube of the throat from the steam nozzle is in the rangeof 0.5 to 0.75 to effect a temperature in the range of 42° C. to 65° C.of the steam air mixture at the outlet of the housing.
 8. The warm airhumidifier of claim 2, wherein the water supply compartment comprise aremovable tray which includes a filling compartment and a maincompartment.
 9. A warm air humidifier, comprising a base, a watercontainer on said base, a water supply compartment in said base having afilling compartment and a main compartment adapted to be supplied withwater from said water container, an evaporating chamber having one endin communication with said water supply compartment, heating meanswithin the evaporation chamber for boiling the water therein to generatesteam, the upper end of said evaporation chamber being closed, a steamnozzle in said upper end for permitting steam to flow from saidevaporation chamber, an upstanding and enclosed housing on said base anaccommodating the upper end of the evaporation chamber, a compartment insaid housing, an air inlet in a wall of said housing in communicationwith said housing compartment, a steam-air outlet formed in the upperportion of the housing, a vertically disposed steam ejector tube in saidhousing compartment, the lower ed of the steam ejector tube being injuxtaposition with the steam nozzle but spaced therefrom to receive astream of steam from the steam nozzle, the upper end of the steamejector tube being connected to said outlet in the upper portion of thehousing, the walls of the lower end of the evaporation chamber being sodisposed and spaced with respect to walls of said water supplycompartment that during the operation of the humidifier the level of thewater in the water supply compartment is maintained at a higher levelthan the water in the evaporation chamber to maintain a pressure withinthe latter on the steam being formed therein to drive the steam throughthe steam nozzle, said steam ejector tube being configured to create aregion of low pressure within the tube upon the flow of steamtherethrough to thereby draw air from the housing compartment andcausing an admixture of steam and air which flows through the upper endof the steam ejector tube for discharge from said housing through saidoutlet.
 10. The warm humidifier of claim 9, wherein the air inlet isdisposed in a sidewall of the housing and the steam-air outlet isprovided in the top of the housing.
 11. The warm air humidifier of claim10, wherein the housing is detachably removable from the base ad carriesat its lower end the evaporation chamber.
 12. The warm air humidifier ofclaim 11, wherein the heating means is secured to and carried by thehousing.
 13. The warm air humidifier of claim 10, wherein a filtermedium is provided within the air inlet to remove particulates from theair entering the housing.
 14. The warm air humidifier of claim 9,wherein the evaporation chamber has an open ended bottom with the wallsof the chamber being spaced from the bottom of the main compartment ofthe water supply compartment and the upper end of the evaporationchamber is closed with a dome shaped protrusion which carries the steamnozzle.
 15. The warm air humidifier of claim 14, wherein the dome shapedprotrusion and the steam nozzle extend above the base and project intothe housing compartment.
 16. The warm air humidifier of claim 14,wherein a baffle is disposed in the evaporation chamber below the steamnozzle to minimize water droplets being carried to the steam nozzle aswell as to muffle the boiling sounds of the generating steam.
 17. Thewarm air humidifier of claim 9, wherein the interior of the steamejector tube has a narrowed portion thereof to form a throat where thesteam from the steam nozzle ad the air from the housing compartmentcombine to form a steam air mixture for discharge from the housing. 18.The warm air humidifier of claim 17, wherein the rate of steam flow outof the steam nozzle is maintained below 0.5 grams/sec cm².
 19. The warmair humidifier of claim 17, wherein the temperature of the steam airmixture being discharged from the humidifier is in the range of 42° C.and 65° C. by maintaining the ratio between the throat diameter of thesteam ejector tube and the distance of the throat from the nozzle in theratio of 0.5-0.75.
 20. The warm air humidifier of claim 17, wherein theratio between the nozzle diameter and that of the throat is in the rangeof 0.1-0.25.